The invention relates generally to information processing systems, and more particularly to computer-pointing devices for use with three-dimensional display systems.
Computer-pointing devices for three-dimensional display systems are known. See for example U.S. Pat. No. 5,767,840 to Selker, and assigned to the assignee of the present patent application, and U.S. Pat. No. 5,699,695 to Canfield et al. The known devices do not lend themselves to the application of force feedback, Selker, or tend to be overly complex, Canfield et al.
A need exists for a simple, low-cost, easy-to-manufacture electro-mechanical transducer for 6-degrees of freedom input and output.
The present invention is a simple device that meets this need. In a preferred embodiment, it includes a spherical control member firmly mounted on a triangular platform that is suspended above a fixed reference by 6 linear transducers. The spherical control member includes a compressible pressure sensor that is used as a xe2x80x9cclickxe2x80x9d mouse button.
Each of the 6 linear transducers is a simple capacitive-type device that provides an output signal proportional to the transducer extension (xe2x80x9clengthxe2x80x9d). The transducers are movably attached in pairs to vertices of the triangular platform. The opposite ends of the transducers are movably attached in a permutation to three points of the fixed reference. The 6 linear transducers extend and contract as the spherical control member is moved in 3-dimensional space. The transducer output signals define a 6-degree-of-freedom vector that precisely specifies the position and orientation of the control member in 3-dimensional space.
In another embodiment of the invention, at least some of the transducers include linear force actuators for inserting force between the transducer endpoints. Electrical signals are applied to the actuators that create force in opposition to change in position, velocity, and rotation of the control member in 3-dimensional space. Thus it is possible to provide a user with a tactile feel that he is pushing against a real force. Alternatively, the actuators can be used to move the control member in a gentle, guiding way during a user-training session.
In yet another embodiment, the invention includes means for maintaining the control member in a fixed relation with respect to 3-dimensional space such that the user must overcome threshold inertia to move or re-orient the control member in the 3-dimensional space.
The present implementation has the advantages of simplicity, low cost, ease of manufacture, simple arithmetic transformations, a single kind of transducer, a linear transducer, a transducer that is easily fitted with a linear motor for adding tactile feedback force.